Incest Big Butt Mother Swapping

Ippei and Hiroyuki were unable to join the sashes in the last tournament they participated in as part of their high school track and field team, and even after graduation they remain lethargic. One day, Ippei confesses to Hiroyuki the reason why he didn't tie the sash. The day before the race, he had a violent affair with his mother, Sakiko, and was unable to run as well as he wanted. And that relationship continues even now. When Hiroyuki heard this, he was not angry, but just envious. He had feelings for his mother-in-law, Yumi. Ippei offers to help Hiroyuki connect the sash of courage, but...